The impact of urban groundwater upon surface water - eTheses ...

q = - k
dh
dx
River
Riverbed
q = the specific discharge (md -1 )
Piezometer
Figure 4.9 Schematic diagram for Darcy Flux Equation
k = conductivity of the riverbed material (md -1 )
dh
dx
MONITORING NETWORKS AND METHODS
dh = the head difference between the river and the piezometer -steady state conditions
assumed (m)
dx = distance from the piezometer screen to the river bed (m)
The values of k were determined from falling head test data analysed with the Hvorslev
method. The value of k derived using this method has been taken as representative of the
vertical conductivity but it will contain a significant horizontal component which, with a
common anisotropy ratio of 10:1 (kx:kz), will have led to an over estimation of the vertical
conductivity. The value of dh was derived at single time point under an assumed steady state
condition. The data were processed with an excel spreadsheet to derive a flux estimate for
each river bed piezometer (Appendix 18).
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